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/* $Id: t_vb_fog.c,v 1.1 2000/12/26 05:09:33 keithw Exp $ */
/*
* Mesa 3-D graphics library
* Version: 3.5
*
* Copyright (C) 1999-2000 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* Author:
* Keith Whitwell <keithw@valinux.com>
*/
#include "glheader.h"
#include "colormac.h"
#include "context.h"
#include "macros.h"
#include "mem.h"
#include "mmath.h"
#include "mtypes.h"
#include "math/m_xform.h"
#include "t_context.h"
#include "t_pipeline.h"
struct fog_stage_data {
GLvector1f fogcoord; /* has actual storage allocated */
GLvector1f input; /* points into VB->EyePtr Z values */
};
#define FOG_STAGE_DATA(stage) ((struct fog_stage_data *)stage->private)
/* Use lookup table & interpolation?
*/
static void make_win_fog_coords( GLcontext *ctx, GLvector1f *out,
const GLvector1f *in )
{
GLfloat end = ctx->Fog.End;
GLfloat *v = in->start;
GLuint stride = in->stride;
GLuint n = in->count;
GLfloat *data = out->data;
GLfloat d;
GLuint i;
out->count = in->count;
switch (ctx->Fog.Mode) {
case GL_LINEAR:
d = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride))
data[i] = (end - ABSF(*v)) * d;
break;
case GL_EXP:
d = -ctx->Fog.Density;
for ( i = 0 ; i < n ; i++, STRIDE_F(v,stride))
data[i] = exp( d*ABSF(*v) );
break;
case GL_EXP2:
d = -(ctx->Fog.Density*ctx->Fog.Density);
for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) {
GLfloat z = *v;
data[i] = exp( d*z*z );
}
break;
default:
gl_problem(ctx, "Bad fog mode in make_fog_coord");
return;
}
}
static GLboolean run_fog_stage( GLcontext *ctx,
struct gl_pipeline_stage *stage )
{
struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
struct fog_stage_data *store = FOG_STAGE_DATA(stage);
GLvector1f *input;
VB->FogCoordPtr = &store->fogcoord;
if (stage->changed_inputs == 0)
return GL_TRUE;
if (ctx->Fog.FogCoordinateSource == GL_FRAGMENT_DEPTH_EXT) {
if (!ctx->_NeedEyeCoords) {
GLfloat *m = ctx->ModelView.m;
GLfloat plane[4];
/* Use this to store calculated eye z values:
*/
input = &store->fogcoord;
plane[0] = m[2];
plane[1] = m[6];
plane[2] = m[10];
plane[3] = m[14];
/* Full eye coords weren't required, just calculate the
* eye Z values.
*/
gl_dotprod_tab[0][VB->ObjPtr->size](input->data, sizeof(GLfloat),
VB->ObjPtr, plane, 0 );
input->count = VB->ObjPtr->count;
}
else
{
input = &store->input;
if (VB->EyePtr->size < 2)
gl_vector4f_clean_elem( VB->EyePtr, VB->Count, 2 );
input->data = &(VB->EyePtr->data[0][2]);
input->start = VB->EyePtr->start+2;
input->stride = VB->EyePtr->stride;
input->count = VB->EyePtr->count;
}
} else
input = VB->FogCoordPtr;
make_win_fog_coords( ctx, VB->FogCoordPtr, input );
return GL_TRUE;
}
static void check_fog_stage( GLcontext *ctx, struct gl_pipeline_stage *stage )
{
stage->active = ctx->Fog.Enabled;
if (ctx->Fog.FogCoordinateSource == GL_FRAGMENT_DEPTH_EXT)
stage->inputs = VERT_EYE;
else
stage->inputs = VERT_FOG_COORD;
}
/* Called the first time stage->run() is invoked.
*/
static GLboolean alloc_fog_data( GLcontext *ctx,
struct gl_pipeline_stage *stage )
{
TNLcontext *tnl = TNL_CONTEXT(ctx);
struct fog_stage_data *store;
stage->private = MALLOC(sizeof(*store));
store = FOG_STAGE_DATA(stage);
if (!store)
return GL_FALSE;
gl_vector1f_alloc( &store->fogcoord, 0, tnl->vb.Size, 32 );
gl_vector1f_init( &store->input, 0, 0 );
/* Now run the stage.
*/
stage->run = run_fog_stage;
return stage->run( ctx, stage );
}
static void free_fog_data( struct gl_pipeline_stage *stage )
{
struct fog_stage_data *store = FOG_STAGE_DATA(stage);
if (store) {
gl_vector1f_free( &store->fogcoord );
FREE( store );
stage->private = 0;
}
}
const struct gl_pipeline_stage _tnl_fog_coordinate_stage =
{
"build fog coordinates",
_NEW_FOG,
_NEW_FOG,
0, 0, VERT_FOG_COORD, /* active, inputs, outputs */
0, 0, /* changed_inputs, private_data */
free_fog_data, /* dtr */
check_fog_stage, /* check */
alloc_fog_data /* run -- initially set to init. */
};
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